| Peripheral nerve was all the nerve besides the central nerve(the brain and spinal cord), and it undertook a variety of physiological functions. Once it received direct or indirect trauma, it would lead to the dysfunction of movement and sensory of the trunk and limbs, which affected people’s normal life seriously. At present, it was difficult to recover the peripheral nerve injury, so the repair of peripheral nerve injury has been one of the clinical problems. This research took frankincense extract as drug trials and rat sciatic nerve injury as the animal model to study the effect and mechanism of frankincense extract on repair of peripheral nerve injury, which provided theoretical and experimental basis for the development of natural drug treating peripheral nerve injury.The experiment used 96 SD rats(half male and half female) to make the sciatic nerve injury model. The rat models were randomly divided into four groups:model control group, frankincense high dose group, frankincense medium dose group, frankincense low dose group. Feed the rats drugs by intragastric administration once a day after surgery. Assess the recovery of neural function after sciatic nerve injury through calculating SFI and gastrocnemius muscle wet weight; detected the relative expression of GAP-43 by western blot; observed the tissue recovery after sciatic nerve injury by HE staining; detected effect on the proliferation of Schwann cells through investigating S100 expression by immunohistochemistry.Results showed:(1) 7, 14, 21 and 28 days after surgery, SFI of all the groups showed a trend of sciatic nerve function recovered gradually; 7 days after surgery, SFI showed no significant difference among groups. 14 and 21 days after surgery, SFI in frankincense extract high-dose group increased significantly(p < 0.05), and frankincense extract medium dose group and low dose group showed no significant difference compared with control group. On day 28, compared with control group, SFI of frankincense extract medium and high dose group improved significantly(p < 0.05). There was no significant difference between the low dose group and the control group at all time points. Prompt recovery of frankincense extract can improve the function after sciatic nerve injury.(2)In each group, the recovery rate of gastrocnemius muscle decreased with time going, and the model control group had the greatest decrease. 7 and 14 days after treatment, gastrocnemius muscle recovery rate in frankincense high dose group was significantly higher than that in the control group(p < 0.05), and there was no significant difference between low and medium dose group and the control group. 21 and 28 days after treatment, recovery rate of gastrocnemius muscle in frankincense high dose group and medium dose group showed significant difference compared with the control group(p < 0.01), and low dose group showed no significant difference. The above results indicated that frankincense extract can improve the function of sciatic nerve after injured.(3)In the control group, 28 days after surgery, the nerve fiber at injury site was reconnecting. There was distinct Wallerian degeneration and myelin sheath disintegration. Vacuoles were present in nerve fibers and spindle cells proliferated. In frankincense extract low-dose group, the nerve fiber at injury site was reconnecting, the adjacent axon degenerated, myelin sheath collapsed, vacuoles were seen in nerve fibers, SCs proliferated. No significant differences were observed in the histology of the injured sciatic nerve between the low-dose group and mediumdose group. But in high-dose group, 28 days after surgery, the injured nerve recovered better than the other groups and SCs proliferated obviously.(4)7 days after surgery, expression of GAP-43 in each test group was no significant difference with the control group. But on day14, 21 and 28, the expression of GAP-43 of frankincense extract high dose group was significantly higher than the control group(p < 0.05). On day28, compared with the control group, GAP-43 expression of frankincense extract high dose group and medium dose group were significantly increased(p < 0.01). There was no significant difference between the low group and control group at each time point. It suggested frankincense extract could upregulate the expression of GAP-43 after sciatic nerve injury.(5)7, 14, 21 and 28 days after surgery, S100 expression in frankincense extract medium and high dose group was significantly higher than that in control group(p < 0.01), and frankincense extract low dose group showed no significant difference compared with the control group. It indicated that frankincense extract could promote Schwann cell proliferation after sciatic nerve injury.In summary, frankincense extract could promote the repair of sciatic nerve injury effectively and the mechanism might be that the frankincense extract could improve sciatic nerve function, improve the expression of GAP-43 and promote the proliferation of Schwann cells after sciatic nerve injured. |
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